Browsing by Author "Liu, TY"

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A novel self-aligned highly reliable sidewall split-gate flash memory
(2006-03-01)
Cho, CYS
;
Chen, MJ
;
Chen, CF
;
Tuntasood, P
;
Fan, DT
A self-aligned sidewall split-gate Flash memory cell is fabricated with overerase immunity. Particularly, the sidewall corner of the floating-gate is deliberately rounded to release the electric field lines encountered in the poly-to-poly erase. The unit cell size of 12.7 F-2 (F is the feature size), formed in a 32-Mb NOR architecture, and the acceptable erase speed of 20 ms for block erase (512 K bits, 16 pages) are quite competitive. Endurance cycles up to 105 confirm the novel cell to be highly reliable as compared with the conventional source-side erase scheme. The bake experiment at 250 degrees C before and after program/erase cycles indicates the cell not only free of extrinsic defects in the manufacturing process but also experiencing excellent retention characteristics. Disturb effects during the programming and read-out operations are examined in detail and the operating conditions for disturbs inhibition are readily determined. We eventually elaborate on the differences between the proposed cell structure and existing ones, as well as on the NAND architecture application.
Active quotation authentication in microsoft word documents using block signatures
(2005)
Liu, TY
;
Tsai, WH
;
資訊工程學系
;
Department of Computer Science
Traditional message authentication does not verify the integrity and the claimed source of quotations in an anonymous message. A new active quotation authentication framework is proposed that allows a reader to authenticate the content and origin of the quotations in a citing document A block signature method is proposed that generates context-sensitive block signatures for an authoritative message, and allows quotation signatures to be generated on-the-fly for arbitrary sub passages by an anonymous author. The block signature method requires a small initial computational effort and storage requirement for block signature generation; has a small quotation signature overhead; and is efficient for quotation authentication.
Analytical calculation for DC inductances of rectangular spiral inductors with finite metal thickness in the PEEC formulation
(2006-02-01)
Kuo, JT
;
Su, KY
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Liu, TY
;
Chen, HH
;
Chung, SJ
Inductances of rectangular spiral inductors with finite metal thickness are evaluated by the partial element equivalent circuit (PEEC) technique. The six fold partial self and mutual inductance integrals resulting from the PEEC partitions are found to have analytical expressions, so that the singularities of the integrands can be overcome and the theoretical or "exact" results can be obtained very efficiently. Via and underpath required for input/output connection can also be included in the calculation. Calculated inductance values for 20 square spiral inductors are checked against measured data published in open literature. Dependence of inductance values on metal thickness is investigated for two specific spiral structures.
Biofunctional ZnO nanorod arrays grown on flexible substrates
(2006-06-20)
Liu, TY
;
Liao, HC
;
Lin, CC
;
Hu, SH
;
Chen, SY
A square pattern of thioctic acid self-assembled ZnO nanorod arrays was grown on a large 4-in. thermoplastic polyurethane (TPU) flexible substrate via an in situ soluthermal process at low temperature (348 K). With the addition of dimercaptosuccinic acid (DMSA), the surface chemistry forms a disordered ZnO phase, and the morphology of the ZnO- DMSA nanorods changes with various DMSA addition times. As evidenced by the Zn-2p3/2, C-1s, O-1s, S-2p, and N-1 s scans of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), DMSA and proteins were conjugated on the single crystalline ZnO nanorods. The photoluminescence (PL) spectra indicated that the optical properties of ZnO nanorod arrays were changed while the DMSA was inserted, and proteins were conjugated. Furthermore, a control test found that the ZnO nanorods show a significant improvement in sensitive characterization over the ZnO film. As another proteins (e. g., human serum albumin, HSA) were bound onto the ZnO- bovine serum albumin (BSA) nanorod arrays, an enhanced ultraviolet emission intensity was detected. On the basis of these results, one might be expected to conjugate specific biomolecules on the biofunctional ZnO nanorod arrays to detect the complementary biomolecules by PL detecting.
Deep hole traps created by gamma-ray irradiation of GaInP
(2001-12-01)
Sung, WJ
;
Liu, TY
;
Yang, SL
;
Huang, KF
;
Tseng, TY
Deep hole traps, created by gamma-ray irradiation of Al/GaInP Schottky diodes grown by metal-organic chemical vapor deposition (MOCVD) were studied by using deep level transient spectroscopy (DLTS) technique. Two distinct deep hole traps, A and B, were observed in the irradiated GaInP samples, According to the analysis of trap concentration in various samples, the trap A is verified as a bulk defect located at 0.29 eV above the valance band. Meanwhile, the trap B is an interface state originated from the junctions of Al/Mg-doped GaInP contacts.
Fuzzy/neural congestion control for integrated voice and data DS-CDMA/FRMA cellular networks
(2000-02-01)
Chang, CJ
;
Chen, BW
;
Liu, TY
;
Ren, FC
;
電信工程研究所
The paper proposes congestion control using fuzzy/neural techniques for integrated voice and data direct-sequence code division multiple access/frame reservation multiple access (DS-CDMA/FRMA) cellular networks. The fuzzy/neural congestion controller is constituted by a pipeline recurrent neural network (PRNN) interference predictor, a fuzzy performance indicator, and a fuzzy/neural access probability controller It regulates traffic input to the integrated voice and data DS-CDMA/FRMA cellular system by determining proper access probabilities for users so that congestion can be avoided and throughput can be maximized. Simulation results show that the DS-CDMA/FRMA fuzzy/neural congestion controllers perform better than conventional DS-CDMA/PRMA with channel access function in voice packet dropping ratio, corruption ratio, and utilization. In addition, the neural congestion controller outperforms the fuzzy congestion controller.
Gamma-ray induced deep electron traps in GaInP
(2001-09-01)
Sung, WJ
;
Liu, TY
;
Yang, SL
;
Huang, KF
;
Tseng, TY
Deep electron traps created by gamma-ray irradiation of Au/GaInP Schottky diodes grown by metal-organic chemical vapor deposition (MOCVD) were studied by using deep level transient spectroscopy (DLTS) technique. Three distinct deep electron traps, G1, G2 and G3, were observed in the irradiated GaInP samples. According to the analysis of trap properties in various samples. trap G1 is verified as a bulk defect located at 0.13 eV below the conduction band, while trap G2 and G3 are interface states originated from the junctions of Au/Te-doped GaInP contacts.
Hemocompatibility and anaphylatoxin formation of protein-immobilizing polyacrylonitrile hemodialysis membrane
(2005-04-01)
Liu, TY
;
Lin, WC
;
Huang, LY
;
Chen, SY
;
Yang, MC
Plasma proteins were covalently immobilized onto polyacrylonitrile (PAN) membrane to evaluate the hemocompatibility and anaphylatoxin formation. This is used as a model to study the effect of protein-adsorption on the blood-contacting response of hemodializing membranes. The proteins used were either platelet-adhesion-promoting collagen (COL) or platelet-adhesion-inhibiting human serum albumin (HSA). The microstructure and characterization of the protein-immobilizing PAN membranes were evaluated by Coomassie dye assay, atomic force microscopy, X-ray photoelectron spectroscopy and water contact angle measurement. PAN-HSA membrane improved not only hemocompatibility including less platelet adhesion, longer blood coagulation times, and higher thrombin inactivity level, but also induced lower complement activation. On the other hand, PAN COL membrane exhibited blood incompatibility, although induced less increase of C3, C4 antigens of serum. Overall results of this study demonstrated that the immobilization of HSA onto the surface of PAN membrane would be beneficial to improve the hemocompatibility and to reduce the anaphylatoxin formation during hemodialysis. (C) 2004 Elsevier Ltd. All rights reserved.
Influence of the aspect ratio of bioactive nanofillers on rheological behavior of PMMA-based orthopedic materials
(2004-10-15)
Liu, TY
;
Chen, SY
;
Liu, DM
;
材料科學與工程學系
;
Department of Materials Science and Engineering
In this investigation, calcium-deficient hydroxyapatite (CDHA) nanocrystals with needle-like geometry were synthesized and incorporated with Poly(methyl methacrylate), PMMA, to form CDHA-PMMA nanocomposites. Rheological behaviors of the PMMA-CDHA melting suspensions were systematically investigated in terms of solid loading and aspect ratio of the CDHA nanoparticles. The maximum solid loadings of nano-CDHA particles with aspect ratios of 7.2, 10.4, and 17 were determined to be 28, 31, and 57%, respectively. An increase in solid concentrations causes pronounced shear-thinning behavior. This result suggests that a strong interaction, including Van der Waals attraction and mechanical interlocking, between the nano-CDHA particles makes the nanocomposite mixture more non-Newtonian. Furthermore, it was found that packing efficiency and yield strength in the suspension were strongly influenced by the aspect ratio, especially above the critical value of 8.8. The obtained critical aspect ratio and solid content provide not only appropriate design in the PMMA-CDHA polymeric suspension for fabrication process but also optimal conditions for the fabrication of orthopedic devices via injection molding or extrusion. (C) 2004 Wiley Periodicals, Inc.
Miscibility, thermal characterization and crystallization of poly(L-lactide) and poly(tetramethylene adipate-co-terephthalate) blend membranes
(2005-12-12)
Liu, TY
;
Lin, WC
;
Yang, MC
;
Chen, SY
;
材料科學與工程學系
Binary blend membranes of biodegradable poly(L-lactide) (PLLA) with poly(tetramethylene adipate-co-terephthalate) (PTAT) copolymer were prepared by solution casting via air evaporation. The miscibility of PLLA/PTAT blends was studied by dynamic mechanical analysis (DMA) and thermal mechanical analysis (TMA) in a tensile mode. Differential scanning calorimetry (DSC) measurement was carried out. The surface microstructure and tensile properties of the blend membranes were examined using atomic force microscopy (AFM) and tensile tester. It was concluded that PLLA/PTAT blends should be partially miscible for all ranges of compositions. Higher roughness and porosity were observed for the blend containing 50% PTAT, suggesting more phase separation occurred. The DSC analysis showed that the fusion enthalpy and crystallinity (X-c) of the PLLA-rich phase decreased with increasing PTAT content. Solidification process strongly suggested that the crystallization rate was accelerated by blending with 25% PTAT content, which served as the nucleation agent. Furthermore, the crystallization rate coefficient (CRC) depended on the blending miscibility and cooling rate in the non-isothermal crystallization process. Besides, PTAT addition could be proved to enhance the thermal stability and elongation of resulting blend membranes, even superior to those properties of poly(lactic acid-co-glycolic acid) (PLGA). (c) 2005 Published by Elsevier Ltd.
On the study of BSA-loaded calcium-deficient hydroxyapatite nano-carriers for controlled drug delivery
(2005-09-20)
Liu, TY
;
Chen, SY
;
Liu, DM
;
Liou, SC
;
材料科學與工程學系
Calcium-deficient hydroxyapatite (CDHA) nano-crystals incorporated with bovine serum albumin (BSA) to form BSA-loaded nano-carriers were synthesized via both in-situ and ex-situ processes. Amount of BSA uptake by the CDHA nanocrystals and subsequent release behaviors of the BSA-loaded nano-carriers were investigated. The amount of BSA uptake by CDHA decreases with increasing pH but a larger amount was observed in the ex-situ compared to in-situ process above pH = 8.0. The release profile showed a bursting behavior for the nano-carrier prepared via the ex-situ process, which is probably due to the desorption of BSA molecules. In contrast, for the sample synthesized via the in-situ process at a higher pH level, a slower release profile without bursting behavior due to the dissolution of the BSA-incorporated CDHA crystal is seen from high solution TEM that indicates different extent of interaction between BSA and CDHA. On the other hand, for the nano-carriers prepared via the same process at lower pH level, a two-stage release profile was detected. An initial bursting release is due to the desorption of BSA from the CDHA surface, followed by a slow release as a result of the dissolution of the BSA-incorporated nano-crystals along its c-axis direction. (c) 2005 Elsevier B.V. All rights reserved.
Study on drug release behaviour of CDHA/chitosan nanocomposites-Effect of CDHA nanoparticles
(2006-05-01)
Liu, TY
;
Chen, SY
;
Li, JH
;
Liu, DM
;
材料科學與工程學系
To explore the effect of nanofiller-polymer interaction on the drug release behaviour from a monolithic membrane prepared by Ca-deficient hydroxyapatite (CDHA)/chitosan nanocomposite, release kinetics was investigated in terms of different synthetic processes, i.e. in situ and ex situ routes, and various amounts of CDHA. It was found that a higher value of diffusion exponent (n) was obtained for the membranes in situ synthesized compared with those ex situ prepared. In addition, the it value of the membranes in situ synthesized increased with increasing CDHA amount, which remained in the range below 10wt.%. However, as CDHA content exceeded 30%, the n value remained constant. It indicates that the drug diffusion mechanism is altered by the CDHA-chitosan interaction which is strongly influenced by both the synthesis process and the concentration of the CDHA nanofiller in the membrane. On the other hand, a lower permeability (P) value of the membranes was observed for those prepared via the in situ process. Furthermore, P value decreased and increased with increasing CDHA amount in the range below and above 10 wi.%, respectively. It demonstrates that CDHA nanofillers act either diffusion barrier or diffusion enhancer for the CDHA/chitosan membranes, which is determined by the concentration of CDHA nanofiller and the synthesis route of nanocomposite. (c) 2006 Elsevier B.V All rights reserved.
Surface characteristics and hemocompatibility of PAN/PVDF blend membranes
(2005-05-01)
Liu, TY
;
Lin, WC
;
Huang, LY
;
Chen, SY
;
Yang, MC
Polyacrylonitrile (PAN) was blended with polyvinylidine fluoride (PVDF) at various ratios and made into membranes. The hemocompatibility of the resulting membranes was evaluated based on human plasma proteins adsorption, platelet adhesion, thrombus formation, and blood coagulation time. The PAN/PVDF blends exhibited partial miscibility according to the inward shifting of their two glass transition temperatures. The microstructures of blend membranes examined using atomic force microscopy (AFM) indicated that the roughness increased with the PVDF content, and the phase separation was too severe to form a membrane when the PVDF content was more than 30%. The water contact angle of PAN/PVDF blend membranes increased with the PVDF content. By blending with 20wt% apolar PVDF the adsorption of blood proteins could be reduced, and hence the platelet adhesion and thrombus formation was also reduced. However, when the PVDF content was 30 wt%, severe thrombogenicity was observed due probably to the more porous structure of blend membrane. These results demonstrated that the hemocompatibility would be improved for PAN/PVDF blend membranes with appropriate hydrophilicity and roughness. Copyright (c) 2005 John Wiley & Sons, Ltd.